1. Field of the Invention
The invention relates to an inkjet recording apparatus, and particularly to an inkjet recording apparatus having a fluid passage through which air is supplied into an ink cartridge as mounted on the inkjet recording apparatus.
2. Description of Related Art
Disclosed in JP-A-9-207347 corresponding to U.S. Pat. No. 5,992,988, there is known an inkjet recording apparatus where a labyrinthine air communication passage in communication with an air communication port is formed in an ink cartridge to restrict flow of air into and out of the ink cartridge through the air communication port in order to prevent evaporation of ink or water in the ink.
Further, in JP-A-9-85963 corresponding to U.S. Pat. Nos. 6,010,213 and 6,450,630 is disclosed another arrangement where an ink container (or an ink cartridge) is detachably attached to a holder (or a mounting portion). In the holder are formed an air communication passage in which an ink-attracting porous material is accommodated, and an ink supply passage connected to a recording head. Two openings in the ink cartridge are connected to these passages, respectively.
However, in the arrangement of JP-A-9-207347 where the labyrinthine air communication passage is formed in the ink cartridge, to ensure a sufficient length of the air communication passage requires an increase in the volume of the ink cartridge. When the volume of the ink cartridge is decreased, on the other hand, the labyrinthine air communication passage can not have a sufficient length or a desired shape.
Further, in the arrangement of JP-A-9-85963 where upon mounting of the ink cartridge the porous material in the air communication passage absorbs the ink to make the pressure inside the ink cartridge negative, evaporation of the ink at the air communication passage and a variation in compression of the porous material make the negative pressure in the ink cartridge unstable.